1. Field of the Invention
The present invention relates to a driving circuit board assembly for a motor and, more particularly, to a driving circuit board assembly including a plurality of axially spaced driving circuit boards.
2. Description of Related Art
FIG. 1 of the drawings illustrates a conventional motor 9 including a driving circuit board 91, a stator 92, and a rotor 93. The driving circuit board 91 includes a plurality of electronic elements 8 such as power electronics switches, resistors, capacitors, Hall ICs, pulse-width-modulation ICs, etc. The driving circuit board 91 is electrically connected to the stator 92 to feed the stator 92 with a driving current for creating a magnetic field to drive the rotor 93.
However, when the motor 9 has a high output power rated, with the electronic elements 8 densely arranged on one side of the driving circuit board 91 and the other side of the driving circuit board 91 being close to the stator 92, the increase of the driving current of the driving circuit board 91 causes a lot of heat, which is generated by the electronic elements 8 on the driving circuit board 91, and results in poor heat dissipation. The lives of the electronic elements 8 are thus shortened. Furthermore, additional electronic elements including temperature sensors, speed detectors, multiplexers, analog/digital converters, microprocessors, etc are incorporated into a motor to provide additional functions including temperature detection, speed detection, etc. Difficulties arise when incorporating these additional electronic elements onto the driving circuit board 91 that is crowded with the electronic elements 8, leading to inconvenience to assembly and aggravation of the heat dissipating problems.